The website is slow, sometimes doesn't work at all

I've used 4 different browsers in the last few weeks, the browser being used is meaningless.
You get the errors regardless of whether you use Opera, Firefox, IE etc.
I recently upgraded from Firefox 2 to version 3. Still get the errors.
Time of day, no correlation for me.
And for those that might bring up the sigs correlation, it's pretty much been established you can get the error and/or slow loading times going to a page with barely any sigs, or a page full of sigs.
I could quite easily have a page full of signatures load up in about 1/4 of a second, but try to go into a new topic which hasn't been posted in yet other than the starter post, and it could take 5 minutes.

Any sort of pattern? Are some times of the day better than others? I get the time out very occasionally, but certainly not daily. I wonder if there is a peak time?

Server Error in Forum Application
An error has occurred while writing to the database.
Please contact the forum administrator.

Support Error Code:- err_SQLServer_save_new_post_data
File Name:- new_post.asp

Error details:-
Microsoft OLE DB Provider for SQL Server
Timeout expired

I'm not talking about loading times for pages as we have 023972 signatures and sh*t that takes a lot of time... I'm talking when you press the link for, say, an specific thread, it takes SO long sometimes to get there, and sometimes, like yesterday a few times, it didn't get there at all and I had one of two possible messages, either "server forum error" or something like that or the IE-generated "Internet Explorer can't open this page" or something. Now, it's not my computer (I have two) nor my conecction (every other website works perfectly... even Mike's slow-as-hell ratingfreak!!).....